The present invention relates to an X-ray sheet film cassette for taking X-ray pictures of body parts forming an angle with one another, the cassette being assembled of two mutually swingable parts hinged one to the other a one side and locatable at the opposite side. One of the cassette parts has thin walls and is constructed for receiving a sheet film supported on the inner surface of a broad or bottom side of the cassette and an edge of the film abuts against the inner surface of a narrow side of the one cassette part which is brought in contact with a part of the patient's body. The other cassette part has a broad side provided with a resilient pressure pad which in closed condition of the cassette presses the sheet film against the supporting surface of the thin-walled cassette part. Preferably, the pressure pad is provided with a reinforcing foil engaging the film.
In conventional, commercially available cassettes of this kind the locking means are arranged on the upper surface of the cover cassette part, above the thin-walled narrow side of the other cassette part. In closing the cassette, the resilient pressing pad of foam rubber which is provided with the reinforcing foil, first engages with its edge remote from the locking means the sheet film and during tilting of the cover cassette part displaces the film away from the thin-walled narrow side toward the opposite narrow side provided with the hinge mount. Since during the picture taking of angular body parts (for example in mammography or in exposing chin and lower jaw) it is desirable that exposed body part be reproduced as close as possible to the other part and the marginal areas of the film should not be positioned in an uncontrolled manner, it is important that the narrow side of the cassette which is in contact with a body part be not only extremely thin (of about 1 mm wall thickness) but also that the film be always in abutment with the inner surface of the thin-walled narrow side. The unavoidable 1mm marginal area (wall thickness of the thin narrow side) of the exposed angular body part does not appear on the X-ray picture. It is therefore a great disadvantage that in conventional cassettes the sheet film is shifted by the pressing pad away from this thin-walled narrow side and the marginal zone of the exposed body part which does not appear on the picture cannot be controlled during the insertion of the film in the cassette and frequently this zone is substantially greater than the wall thickness of the side of the cassette which is applied to the patient's body.